Sheet metal duct



A. H. BERGER ET AL Oct. 3, 1944.

SHEET METAL DUCT Filed July 21, 1941 3 Sheets-Sheet 1 ATTORNEY .ql III/ A. H. BERGER ET A Dot. 3, 1944.

' SHEET METAL DUCT 3 Sheets-Sheet 2 Filed July 21, 1941 3, 1944. A. H. BERGER ET AL 2,359,725

SHEET- METAL DUCT v Filed July 21, 1941 3 Sheets-Sheet 3 INVENTORS fiwaesw 565x59 ATTOR EY Patented Oct. 3, 1944 SHEET METAL DUCT Andrew H. Berger and Allan S. Pinsker, Pittsburgh, Pa., assignors to David Berger, Pittsburgh, Pa.

Application July 21, 1941, Serial No. 403,250

10 Claims.

This invention relates to improvements in sheet metal ducts, such as are employed for conveying heated, cooled or otherwise conditioned air.

In installing ducts for air conditioning lines in new buildings, as well as in old buildings, the location of beams and joists places a limitation on the space available for the ducts and fittings that must be used. Also, where many lines come 01f of a trunk line, it is necessary to increase the area of the trunk as the line approaches the source, to provide the capacity needed to supply the branch lines. It heretofore has been proposed to connect branch connections into the sides of the trunk line in such manner that the opening for the branch connection is at the side of the trunk, and thus avoid using excessively large ducts. However, such installations as heretofore proposed require cutting out the main or trunk duct at the installation to fit the branch connection thereto. This involves not only a waste of material, but the time of the workmanto fit in the branch connection, as it actually requires some fabrication of the duct at the installation.

It is an object of the invention to provide a pre-fabricated reducing branch or take-off connection which may be installed without cutting either duct or connection at the installation.

Another object is to provide a prefabricated reducing branch take-01f or connection that requires stocking only a small number of standard parts.

Another object is the provision of a sheet metal fitting which replaces the combination of a trunk increases, take-01f and'stack adapter heretofore employed in sheet metal duct work.

Another object is the provision of a sheet metal fitting which may be made with a minimum of waste material.

A further object is the provision of a separable takeoff connection and duct wherein either the duct or the takeoff connection may be replaced or substituted and which requires no cutting for the substitution.

A further object is the provision of a separable takeofi connection and duct which are interchangeable and require no fitting or cutting for installation.

A further object is the provision of interchangeable takeofif connections and ducts which, when combined, constitute a duct of sturdy construction which is not easily collapsed, and which may be separated to facilitate storage or transportation.

A further object is the provision of interchangeable ducts and takeofi connections which may be united by a snaplock connection.

A further object is the provision of inter-'- changeable ducts and takeoff connections which may be assembled into a trunk line with greater speed than other types of fittings heretofore employed.

In the accompanying drawings, wherein preferred embodiments of the invention are illustrated by way of example, a

Figure 1 shows a preferred embodiment of our invention comprising a channel and top takeoff,

Figure 2 is an end view of Figure 1 as viewed from the right,

Figure 3 is a section of a IIIIII of Figure 1,

Figure 4 is a layout of a detail,

Figures 5 and 6 are side and plan views respectively of a detail,

Figure? is a top view of a further modifica tion of the invention,

Figure 8 is a side view of the top takeofi shown in Figure 1 looking downward as seen in Figure 1, r v

Figure 9 is an inverted side view of the side takeoff shown in Figure 7, v

Figure 10 is a side view of the round side takeoff shown in Figure 7,

Figure 11 is a section of Figure.8,

Figure 12 is an end view of Figure 9 as viewed from the left,

Figure 13 is an end view of Figure 10 as viewed from the left,

- Figures 14, 15, 16 and 1'7 are sectional views illustrating types of joints employed for securing various parts together,

Figure 18 is a plan view of the throat detail of a top takeofi,

Figures 19 and 20 show theside cheeks of a top takeoff,

Figures 21, 22 and 23 show one cheek, the heel, and the other cheek respectively of a rectangular side takeofi in the relative positions shown in Fig. 12,

Figure 24 shows thethroat portion of a rectangular side takeofi, and

Figures 25, 26 and 27 show the panels;- throat portion and heel respectively of a round side detail taken on line taken on line XIXI takeoff.

3 to provide panels 4, 5 and 6. The channel member has edges I and 8 extending the length of the open side thereof, and the edges 9 at one to and, in use, the hook I4 engages a punched up projection I5 of the adjacent duct wall I6 which overlaps the edge 9. The edges II, I8 and I9 at the other end which may be considered the inlet end, are adapted to receive the snap lock hooks I0 of an adjacent trunk duct section 2I.

The standard sheet metal ducts in general use have one dimension fixed at eight inches and the other cross sectional dimension may be varied in multiples of two inches. Thus, the dimensions of standard ducts will be eight by two inches, eight by four inches, eight by six inches, etc., up to any desired size, although sizes above eight by fourteen inches are not commonly encountered. It will be observed that the missing panel or open side of the channel I is a standard width, namely, eight inches. According to one feature of the invention, this channel is adapted to interchangeably receive any one of a number of types of takeoff ducts of varying sizes, as will hereinafter appear.

In Figure 1 there is shown a channel member I assembled with a duct of the type known as a top takeoff duct, designated generally by the numeral 25. This branch fitting or takeoff 25 comprises a necked channel portion 26 made up of the Walls 3|, 32 and 33, the wall 32 being the same width as the open side of channel I, viz., eight inches wide, and the edges 34 and 35 of walls 3| and 33 extend the length of the open side of channel member I and may have suitable fastening means thereon, such as snap lock hooks I6, adapted to snap over the edges 1 and 8 of the channel member I so that walls SI and 33 form a continuation of walls 4 and 6 of the channel member, while'wall 32 completes the closing of the channel to form a duct which at the inlet is substantially the same dimensions as standard duct 2I connected thereto. The snap lock hooks I6 carried by the end of standard duct 2| snap over the edges I'I, I8 and I9 of channel I and the forward edges 36, 31 and 38 of walls SI, 32 and 33 respectively to hold the sections assembled to form a conduit.

-,-. 48 (Fig. l).

An intermediate wall 39 is provided suitably fastened to the sides of branch fitting 25 and is so located that it, together with the panels 4, 5 and 6 of the channel I at the inlet end form a reduced duct of substantially the same dimensions as the channel I. provides a channel of any desired dimensions, for example 3%, inches by twelve inches connecting with the adjacent trunk duct section 2I (Fig. 1), and the branch connection or outlet open- The neck portion 26 ing 4| enters this channel between the forward end 42 of intermediate wall 39 and the rearward edge 43 of neck portion 26, as more clearly shown invFigure 8. V

In Figures 4, 5, 6 and 18 to 27 we show layouts of the various takeoff connections, no allow- .1

ances being shown for seams excepting where and E are spot welded together.

desired, they may be made of one piece. A cheek -C (Figure 19) is cut out in the general shape of an L with a quadrant shaped portion having a curved edge 46a and an extension piece 48. A throat D (Figure 18) has its edge struck up at 53 (Figs. 1 and 18) and a notch 54 formed in one edge of an extension strip 56 divides that edge into sections 51 and 58, this notch being located at a position from edge 53 equal to the length of extension 48 of part C. The edge portion 58 of strip D now is struck up at a right angle on the dot and dash line and is fastened to the edge 58a of cheek C by a double seam, for example as illustrated in Figure 14 with the right end of strip 48 next to turned up edge 53 so that cheek 0 thus lies at right angles to strip 56, and heel A is suitably fastened along edge 46 to curved edge 46a of cheek C, with the end 15 adjacent upper edge I4 of the cheek and the strip B adjacent edge 59, preferably by a double seam.

Another sheet E (Figure 4) is bended at one side edge to form a struck up side edge GI and is fastened along the side edge 51a to edge 51 of throat D by a Pittsburgh or hammered lock joint as shown in Figure 15 the sheet E thus lying adjacent cheek C with the end 66 extending beyond the curved edge thereof to form the edge If desired, the bent up edge 6| may be made separate from sheet E and secured thereto in any suitable manner. The end edge 59a. of sheet E now is folded inwardly over edge 59 of cheek C as shown in Figure 8 and sheets C The offset cheek G (Figure 20) now is bent at lines 65 and 66 toprovide an offset for a change in dimension and is fastened along edge 45a to edge 45 of heel A by a Pittsburgh lock joint, and

-: along edges 68 and II to edge 68a, and Ila. of

throatD by a double seam. The snap lock hooks then are secured to the edges I4 of cheek C, 53 of throat D, I5 of heel A and 16 of offset cheek G. One snap lock hook secured over edges 11 of strip B and over edge 6| of sheet E serves to rte-enforce these strips and keep edges I9 and III in abutting relation. Thus the lower edge 35 (Fig. 2) is made up of edges 1! and 6|. The other snap lock hook is secured along edge 34 of the extension of throat D. End edge 60 of sheet E also receives a snap lock hook so that when the takeoff is assembled to a channel member I the edge 60 complements the edges 9 thereof.

Other types of branch connections which may be employed are shown in Figures 7, 9, 10, 12 and 13. Referring. to Figures 9 and 12, there is illustrated what is known as a rectangular side takeoff. This comprises aneck portion 99 of channel shape, the channel being formed by walls 9I, 92 and 93 (Figure 12) which neck portion is adapted to co-operate with a channel member I in the same manner as neck 26 shown in Figures 1 and 2 to form the inlet end of a duct substantially as explained in connection with Figures 1 and 2. A wall 95, corresponding to wall 39 of Figure 2, is adapted to cooperate with the duct I to provide a reduced duct at the outlet end and the branch connection opening 96 enters between forward edge 42 of wall 95 and bended edge or corner 43 of neck portion 90.

This rectangular side takeoff is made of a bottom cheek H (Figure 21) and a heel J (Figure 22) which are joined together at edges IUI and IEHa at right angles by a Pittsburgh lock joint, the heel J being suitably curved to conform to curved edge IOI. A top offset cheek K is bent at I03 and I64 to provide an offset for a change in dimension, and is-J'oined along edge I05 to edge I05a of heel J by a Pittsburgh lock joint at right angles to cheek K, the edge I28 thus coming into substantially the same plane as edges I25 and I26 of cheeks H and K, with the edge I24 at the crotch thereof. A throat M (Figure 24) then is bent at 43a. and I08 and is joined along edges III] and III to edges HM and Illa respectively of cheek K by a double seam, and is similarly joined along edges H4 and H5 to edges H40, and II5a respectively of cheek H thus bringing edge I 21 into the same plane as edges I26, I28 and I25. A sheet 95 similar to sheet E (Figure 4) but having the turned over portion 6| omitted, is then joined along its side edges to edges I22 and I23 of checks H and K respectively by a Pittsburgh lock joint, and end 59a is folded over end I24 of heel J. The snap lock hooks then are added to edges I25, I26, I21 and I28 and to edges I29 and I30.

Figures 7, and 13 show a round side takeoff I35 which comprises a neck portion I36 having walls I31, I38 and I39 which co-operate with a channel member I to form the inlet end of a duct substantially as explained in connection with Figure l. A sheet- I4I provides a reduced duct at the outlet end of the channel, and the round branch connection I46 enters between forward edge 42 of sheet MI and edge or corner 43, as shown in Figure 10.

The round takeoff is made of two identical top and bottom panels P (Figure 25), a heel Q (Figure 26) bent up at 43b, a throat R (Figure 2'7) and a sheet I4I (Figure I3) similar to sheet E but wider and having both edges turned up like edge 6!. The two panels P are connected along edges I5I to heel Q along edges I5Ia by a groove seam and edges I53 of the two panels P are connected to throat R along edges I53a by a groove seam. Edges I55 of panels P then are connected to edges I55a of heel Q by a double seam. Edge 59a of sheet I4I then is folded over hemmed edge I6I of throat R and is spot welded to throat R. thus bringing edge 8| into abutting relation to edge I56. Crimped collar I62 then is secured to the edges I63, I64 and I65 of the panels P, Q and R by an elbow edge as'shown in Figure 16, and the snap lock hooks are applied to the turned up side edges of sheet MI and edges I61 of panels P, and serve to hold the edges I67 in alignment with the turned up side edges of sheet MI and in abutting relation.

In Figure 7 the two branch connections 96 and I35 are not connected to a channel I, but are connected by two fiat sheets I'II (one not shown), the edges I12 and I13 thereof being received in the snap lock hooks II]. This construction is desirable when two branch connections are to be used in a common length of duct, and in this construction the equivalent of channel I may be considered as being provided by the side panels I'll and one of the takeoff members 96 or I35.

What we claim and desire to secure by United States Letters Patent is: V 1

1. A branch connection comprising a throat portion having an extension strip, a cheek having a quadrant shaped portion and having an extension secured to the throat extension strip for a portion of its length and at substantially a right angle thereto, a tapered curved heel .portion havin a lateral extension at its smaller end, the curved edge of said quadrant cheek being secured to the edge of said heel portion on the same side as the lateral extension, an offset cheek secured at its edges to said heel portion and throatportion, a sheet having one side edge secured to the remaining edge of the throat extension, and having an end edge folded over the quadrant cheek and the other side edge bent over, and snap lock hooks overlying the throat extension strip and bent over side edge and heel extension.

2. A branch connection comprising a throat portion having an extension strip, a cheek having a quadrant-shaped portion and having an extension secured to a portion of the throat extension strip and at substantially a right angle thereto, a tapered curved heel portion having a lateral extension at its smaller end, the curved edge of said quadrant portion being secured to the edge of said heel portion on the same side as said lateral extension, an offset cheek secured at its edges to said heel portion and throat portion, a sheet having two bent over side edges one of which is secured to the remaining edge of the throat extension at right angles thereto and having an end edge folded over said quadrant portion, a snap lock hook overlying the lateral heel extension and the other bent over side edge of said sheet, and a second snap lock' hook on the edge of said throat extension strip, and a third snap lock hook on the remaining end edge of said sheet.

3. A branch connection comprising a throat portion having an extension strip forming one edge of a channel, a cheek having a quadrantshaped portion and having an extension secured to a portion of the throat extension strip and at substantially a right angle thereto, a curved heel portion having a lateral extension at one end, the curved edge of said quadrant portion being secured to the edge of said heel portion on the same side as said lateral extension, an offset cheek secured at its edges to said heel portion and throat portion, a sheet secured by one side edge to the remaining edge of the throat extension strip and having an end edge folded over the quadrant portion, said sheet having a bent over side edge located in alignment with said lateral heel extension to form an edge of said channel, snap lock hooks on the edges of said channel and a complementary channel member having edges adapted to engage said snap lock hooks to form therewith a reducing duct with a branch connection at right angles thereto within the length of the complementary channel member.

4. A branch connection comprising a channel member having an outer wall and side walls providing two edges extending the length of the channel member and forming the open side thereof, a wall set back from said edges and extending part of the length of said channel member, the outer wall of said channel member having a portion parallel to said set back wall and a portion extending at an angle thereto forming part of a branch fitting to provide a gradual change in direction of flow, and a complementary channel member having two edges forming the open side thereof, and means for removablysecuring said latter channel member in edge to edge relation with the first channel member to form a reducing duct with the set back wall and a takeofi connection with said outer wall.

5. A branch connection as defined in claim 4 wherein said means for removably securing said channel members together comprises a snap lock joint extending along said edges.

. 6. A branch connection comprising a pair of cheek members having quadrant portions with extension strips adapted to provide the edges of a channel, one of said cheek members having a bend where it joins its extension strip, a throat member having a rectangular portion and a tapered portion joined to said cheek members, a heel joined to the curved edges of said quadrant portions, and a sheet joined at its sides to said extension strips and having one end folded over an edge of said heel.

'7. A branch connection comprising a pair of cheek members having quadrant portions with extension strips adapted to provide the edges of a channel, and tongues at one end, one of said cheek members having a bend Where it joins said strip, a throat member having a rectangular portion and a tapered portion joined to said cheek members with a tongue at the end of said tapered portion, a generally triangular heel having a tongue opposite its base and joined to said quadrant portions, a sheet joined at its sides to said extension strips and having one end folded over the base of said heel, snap lock hooks on said channel edges, and a complementary channel member having edges adapted to engage said snap lock hooks whereby a reducing duct having a branch connection is provided.

8. A branch connection comprising'a pair of cheek members of generally rectangular shape having a tapered extension at one corner merging in an arcuate edgea heel comprising a generally rectangular portion having tapered edges merging in an arcuate edge and secured to said cheeks with the arcuate edges adjacent, a. throat of generally semi-circular shape secured to said cheeks with its curved edge adjacent said arcuate edges and having its straight edge bent over, a sheet having one end edge folded over the bent over edge of said throat and having bent over side edges in alignment with edges of said cheeks to form edges of a channel member, snap lock hooks on the latter, and a collar secured to said arcuate edges.

folded edge of said throat and having bent over side edges in alignment with edges of said cheeks, snap lock hooks on said latter edges, a collar secured to said arcuate edges, and a complementary channel member having edges adapted to engage said snap lock hooks whereby a reducing duct with a circular branch connection is provided.

10. A branch connection comprising a channel member having an outer wall and side walls providing two edges extending the length of the channel member and forming the open side thereof, a wall set back from said edges and extending part of the length of said channel member, the outer wall of said channel member having a portion parallel to said set back wall and a portion extending at an angle thereto forming part of a branch fitting to provide a gradual change in direction of flow, wall members having edges removably held in juxtaposition to the edges of the channel member which form the open side of said channel member, and means substantially closing the space between the opposite edges of said wall member whereby a reducing duct having at least one branch connection is formed.

ANDREW H. BERGER. ALLAN S. PINSKER. 

